Debt (Narratives) (Details) - USD ($)		3 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	May 18, 2023	Mar. 31, 2023
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 175,000,000
Outstanding borrowings	$ 527,560,000	$ 527,560,000
Current portion of long-term debt and finance lease obligations	40,619,000	40,619,000			$ 40,604,000
Deferred Costs	7,718,000	7,718,000			6,323,000
Accumulated Amortization, Deferred Finance Costs	2,048,000	2,048,000			1,815,000
Unsecured credit lines	$ 2,400,000	2,400,000
Amount drawn on unsecured credit lines		0
Proceeds from Issuance or Sale of Equity		$ (2,046,000)	$ 0
Lessee, Finance Lease, Term of Contract	23 years	23 years
Operating Income (Loss)		$ 21,448,000	22,817,000
Short-term Debt	$ 40,000,000	40,000,000
Debt Instrument, Periodic Payment, Principal		10,000,000
Debt Instrument, Periodic Payment		1,529,000
Debt Instrument, Increase (Decrease), Other, Net	75,000,000
Amortization of Intangible Assets		6,877,000	$ 6,535,000
Accounts Receivable, after Allowance for Credit Loss, Current	165,050,000	165,050,000			151,451,000
Line of Credit Facility, Increase (Decrease), Net		75,000,000
UNITED STATES
Line of Credit Facility [Line Items]
Accounts Receivable, after Allowance for Credit Loss, Current	80,441,000	80,441,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Accumulated Amortization, Deferred Finance Costs	1,846,000	1,846,000			1,611,000
Deferred Costs, Noncurrent	4,826,000	4,826,000			4,027,000
Required payments [Member]
Line of Credit Facility [Line Items]
Current portion of long-term debt and finance lease obligations	6,116,000	6,116,000
Secured Debt | Asset-Backed Securities, Securitized Loans and Receivables
Debt Disclosure [Abstract]
Long-term Debt	45,000,000	45,000,000
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	55,000,000	55,000,000
Accumulated Amortization, Deferred Finance Costs	15,000	15,000
Long-term Debt	45,000,000	45,000,000
Debt Issuance Costs, Gross	533,000	533,000
Secured Debt | Loans [Member]
Line of Credit Facility [Line Items]
Debt Issuance Costs, Gross	2,286,000	2,286,000			$ 892,000
New Revolving Credit Facility
Line of Credit Facility [Line Items]
Outstanding letters of credit	15,837,000	15,837,000
Increase in Deferred Costs, Noncurrent		799,000
New Revolving Credit Facility | Standby Letters of Credit
Line of Credit Facility [Line Items]
Outstanding letters of credit	15,364,000	15,364,000
New Revolving Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Outstanding letters of credit	473,000	473,000
New Revolving Credit Facility | Unsecured Lines of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	12,813,000	12,813,000
Outstanding borrowings	$ 12,474,000	$ 12,474,000